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Thyroid hormones have pleiotropic effects and act in the heart, brain, skeletal muscles, and bones, among other sites. Along with body weight and energy expenditure, thyroid hormones help regulate metabolic processes necessary for normal growth and development in adults. [1] Subclinical hypothyroidism (SCH) is when serum thyrotropin is elevated and serum levels of free thyroxine are normal with few or no hypothyroid symptoms. [2] Some nonspecific symptoms may include tiredness, constipation, cognitive problems, and dry skin. [3]

To determine the benefits of levothyroxine replacement in elderly individuals with subclinical hypothyroidism

Study Groups

Levothyroxine (n= 368); placebo (n= 369)

Methods

Patients received either levothyroxine 50 mcg daily (or 25 mcg in patients with a body weight of less than 50 kg or history of coronary heart disease) or matching placebo, with stratification according to country, sex and starting dose. Eligible patients had to be 65 years or older and have persistent subclinical hypothyroidism, defined as an elevated thyrotropin level (4.60 to 19.99 mIU per liter) that was measured on at least two occasions that were 3 months to 3 years apart, with a free thyroxine level within the reference range. Dose adjustment in the levothyroxine group was aimed to result in a thyrotropin level within the reference range of 0.40 to 4.59 mIU per liter. The Thyroid-Related Quality-of-Life Patient-Reported Outcome measures Hypothyroid Symptoms score (4 items) and Tiredness score (7 items); each scale ranges from 0 to 100, with higher scores indicating more symptoms and tiredness, respectively.

Duration

12 months

Primary Outcome Measure

Change in Hypothyroid Symptoms score and Tiredness score on a thyroid-related quality-of-life questionnaire at 1 year from baseline

Treatment with levothyroxine in older persons with subclinical hypothyroidism provided no symptomatic benefits.

In the United States, the typical elderly patient takes an average of 14 to 18 prescriptions each day. The increased risk for drug-drug interactions that accompanies widespread polypharmacy among this patient population, along with the changes that come with aging, can affect medication safety and efficacy. If levothyroxine does not provide any benefits in specific patient populations, then it may be disadvantageous to add medications to the list of prescriptive agents geriatrics use. The funding that went into conducting a trial on a subclinical condition may have been misappropriated in that the nonspecific symptoms may be indistinguishable from increasing age.